The background of the invention will be discussed in two parts.
1. Field of the Invention
This invention relates to anchors, and more particularly to a folding anchor for small watercraft.
2. Description of the Prior Art
Anchors generally include a shank with a fluke arrangement at one end of the shank, the other end of the shank being connected to an anchor chain. Generally, the flukes are attached to the shank to permit a limited amount of angular movement. When the anchor is lowered into the sea, the flukes engage the sea bottom, with the shank extending at an angle to the sea bottom in a forward direction, that is, in the direction of the boat. For release of the anchor from engagement with the sea bottom, the boat direction is reversed to provide a direction of force thereon opposite to the direction of engagement of the flukes. To facilitate release, some anchors have been formed with two-piece shanks coupled for limited pivotal movement at a point intermediate the ends of the overall shank.
One such anchor is disclosed in U.S. Pat. No. 103,205, entitled "Anchor", such patent issuing on May 17, 1870 to Law. The anchor of this patent includes a two piece shank, with the upper shank piece being pivotable through a limited angle relative to the lower shank, to which is attached a fluke assembly, which is likewise pivotable through a limited angle.
Another anchor construction is shown and described in U.S Pat. No. 2,720,184, entitled "Articulated and Self-Locking Shank for Anchor", issued to Polenz on Oct. 11, 1955, such patent disclosing an anchor with a two-piece shank, the interconnection of the two pieces being by means of a keyhole slot engaged by a block member. In one position, the block is locked within the narrow neck of the slot with the two shank pieces in axial alignment. When force is exerted by the anchor chain in an opposite direction, the upper shank moves rearwardly relative to the lower shank until the block is in the enlarged portion of the keyhole, thereby permitting pivoting to facilitate release of the anchor from the sea bottom.
U.S. Pat. No. 2,905,128, entitled "Anchor", issued Sept. 22, 1959 to Northrop, and discloses an anchor having a removable guide, or stock member, which may be secured to the shank for storage or attached in perpendicular relation to a fluke retaining cross member.
Another example of an articulated anchor structure is disclosed in U.S. Pat. No. 3,263,642, entitled "Boat Anchor", which issued to Wilson on Aug. 2, 1966, the anchor including a unitary fluke formed of plate metal with first and second symmetrically arranged slots with a common origin. The shank is formed as a yoke with a bar engaging the slot at the origin, with the bolt able to traverse either slot to facilitate removal of the flukes from engagement with the sea bed.
Some anchors have been constructed to permit folding of the flutes and stock arms against the shank, such as shown in U.S. Pat. Nos. 3,215,111 and 3,807,340, the former being issued to McDaniel on Nov. 2, 1965, and the latter being issued to Diorio et al on Apr. 30, 1974. In both patents, the anchors are of the conventional Navy type and have the stock arms pivotally attached to the shank adjacent a first end thereof, with the flukes pivotally attached to the shank adjacent the other end thereof, with the plane of pivoting of the stock arms perpendicular to the plane of pivoting of the flukes. The Diorio anchor includes a spring member encircling the rod-shaped shank to spring load the stock arms to the open position.
An anchor including flukes which may be physically detached from the shank for storage is shown and described in U.S. Pat. No. 3,822,666, entitled "Anchor", which issued to Blomberg on July 9, 1974.
The last three patents enumerated above concern themselves with anchors of the folding type, with the Blomberg and McDaniel anchors being more suited for small pleasure craft usage. The flukes formed of plate metal, as shown in Blomberg, are of widespread use in small craft anchors of recent vintage. Although the Blomberg anchor permits detachment of the flukes for storage and transportation by removal and reattachment of bolts, the anchor should be reassembled prior to casting off, thereby eliminating any storage space advantage while at sea. On the other hand, while the McDaniel anchor permits folding to a relatively small overall configuration, the length of the folded anchor is the same as the length of the shank. Furthermore, such Navy anchors do not have widespread acceptance among small pleasure craft users.
Another anchor is shown and described in U.S. Pat. No. 3,716,012, entitled "Anchors for Marine Use", issued to Wright on Feb. 13, 1973, which discloses an anchor having a plowshaped head pivoted to the shank.
An anchor which includes spring loaded flukes is shown in U.S. Pat. No. 3,793,977, entitled "Vessel Anchor", which issued Ziegler on Feb. 26, 1974. The flukes are maintained against the shank against force of the spring bias by a ring member which is released on dropping the anchor by a telescoping tubular shank arrangement, expansion of which withdraws the ring member out of engagement with the flukes to permit pivoting under force of the springs.
An "Adjustable Anchor" shown and described in U.S. Pat. No. 3,964,420, issued to Stelling on June 22, 1976, the anchor including means for exchanging parts to form anchors of different configurations.
Another "Anchor" is shown and described in U.S. Pat. No. 4,369,727, issued to Fasco on Jan. 25, 1983, the anchor includes a fluke release mechanism actuated by an articulated shank mechanism which releases the fluke assembly to permit pivoting when the angle of the anchor chain is above a critical angle.
U.S. Pat. No. 4,385,584, entitled "Boat Anchor", issued to Simpson, III, on May 31, 1983, and discloses an anchor having removable fluke assemblies which enable compact storage of the anchor.
Another "Collapsible Boat Anchor" is shown and described in U.S. Pat. No. 4,596,202, which issued to Brewster on June 24, 1986, the anchor including a fixed grapple and a movable grapple.
In accordance with an aspect of the invention, it is accordingly an object of the invention to provide a new and improved foldable small craft anchor.